This invention relates generally to the processing of printed circuit boards having mounted thereon electric components for forming good solder joints. More particularly, the present invention is concerned with an apparatus for applying molten wax over the component side of the printed circuit board, the applied wax after solidification serving as a bond for the fixation of the electric components to the printed circuit board.
For the purpose of providing uniform, steady joints between component leads and circuits printed on the board, a technique is proposed in which the electric components-bearing board is first subjected to a dip soldering treatment for providieng temporary joints between the electric components and the board and the resultant board, after cutting the leads depending from the underside of the board, is contacted with a standing wave of molten solder ejected from a nozzle.
This technique, however, suffers from drawbacks that the quality of the electrical components may be deteriorated through the double soldering treatments and the apparatus becomes large in structure. Moreover, the contact of the temporarily joined components with the ejected, running molten solder may cause the leads to come off from the through holes of the board.